<?php 
$i=0;
foreach ($sintomas as $s): ?>
   
        <div class="form_grid_12">

            <label class="field_title" style="background: <?php echo $s['Alerta']['estilo']?>">
                <?php echo $s['Concepto']['signo']?>
            </label>
            <div class="form_input">
                <span >
                    <input name="data[ConceptosPaciente][<?php echo $i?>][concepto_id]" class="checkbox" type="checkbox" value="<?php echo $s['Concepto']['id']?>" tabindex="2">
                </span>
            </div>
        </div>
    <br/>
<?php 
$i++;
endforeach; ?>